Satellite systems have been used extensively to provide a variety of satellite-based services and functions. For example, current satellite systems provide communications services, broadcast and multi-cast services, earth imaging, radar, weather system monitoring, and astronomical observations, among other things.
A satellite system may consist of a single satellite or a plurality of satellites (e.g., a “satellite fleet”) whose functionality are combined in some manner. Satellites may travel in geostationary orbits (GSO) or non-geostationary orbits (NGSO), and are referred to as GSO satellites or NGSO satellites, respectively. A satellite of a single satellite system typically is a GSO satellite, so that the satellite may provide continuous service over a distinct coverage area on the surface of the earth. Satellite fleets may include GSO and/or NGSO satellites. In order to provide continuous coverage, the orbital planes of the satellites within an NGSO satellite fleet typically are separated by some nodal separation angle.
To deploy a satellite fleet, satellites are placed into orbit using launch vehicles. In some cases, a single satellite is carried into orbit by a single launch vehicle. Because launch vehicles and launch operations are expensive, implementing a satellite fleet using single-satellite launches may be uneconomical, in some cases. Accordingly, some satellite fleets have been implemented by launching multiple satellites within a single launch vehicle. In a multiple-satellite launch, the satellites are structurally connected together using a special adapter or dispenser. Although some economies are gained through multiple-satellite launches, the special adapters or dispensers add launch mass and cost. Additionally, once the satellites are released from the launch vehicle (e.g., the payload fairing), they operate in the same plane or at least some of the satellites perform booster rocket burn operations to establish appropriate nodal separation between the satellites' orbital planes. To have the fuel capacity to perform the booster rocket burn operations, satellite fuel tanks are made to accommodate the extra fuel, which also adds extra launch mass.
NGSO operation may have the benefit of improved coverage for higher latitudes. However, NGSO operation suffers from a wider range solar beta angles (i.e., the angle between a satellite's primary axis and the direction of the sun). Because it is desirable to orient a satellite's solar panels perpendicular to the direction of the sun while simultaneously pointing the satellite's downlink antenna toward the intended coverage area, NGSO satellites include relatively complex steering mechanism and multiple gimbals to achieve solar panel orientation and downlink antenna steering.
It is desirable to provide methods and apparatus for economically and reliably implementing a satellite fleet to provide satellite-based services. In addition, it is desirable to provide satellites capable of providing the satellite-based services, which have reduced mass and/or complexity when compared with traditional satellites. Other desirable features and characteristics of embodiments of the inventive subject matter will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.